Pro-apoptotic effects of 5-fluorouracil on ameloblastoma in vitro: Exploring the potential of topical 5-FU ointment in adjunctive therapy.

Objective: This study aimed to evaluate the pro-apoptotic effects of 5-fluorouracil (5-FU) on ameloblastoma (AM) through in vitro experiments and to explore its potential as a topical adjunctive therapy following surgery.

Methods: Primary AM cells and freshly resected tumor tissues were treated with 5 μM 5-FU for 48 h. Apoptotic changes were assessed via transmission electron microscopy (TEM), TUNEL staining, and flow cytometry. Cell proliferation and viability were evaluated using EdU incorporation and CCK-8 assays. Transcriptomic profiling and Gene Ontology (GO) enrichment analyses were conducted to investigate underlying mechanisms.

Results: 5-FU treatment markedly induced apoptosis in AM tissues and cells. TEM revealed abundant apoptotic bodies, with a mean count 2.01-fold higher than controls (p < 0.05). TUNEL staining demonstrated a 2.66-fold increase in apoptotic area (p < 0.01). Flow cytometry showed a 4.70-fold rise in early apoptotic cells (Annexin V⁺/PI^-) and a 25.5 % decrease in viable cells (Annexin V^-/PI^-) (p < 0.01 and p < 0.05, respectively). EdU incorporation decreased by 35.0 %, and CCK-8 assays indicated a 34.5 % reduction in cell viability (p < 0.01). Transcriptomic analysis revealed downregulation of cell cycle-related genes (CCNB1, CCNB2) and enrichment of pathways involved in cell cycle arrest and apoptosis.

Conclusion: 5-FU effectively induces apoptosis and inhibits proliferation in AM cells, likely through disruption of cell cycle progression. These findings support the potential use of topical 5-FU as an adjunctive pharmacologic strategy in the post-surgical management of ameloblastoma.